Harrison F L, Anderson S L
Health and Ecological Assessment Division, Lawrence Livermore National Laboratory, California 94550.
Radiat Res. 1994 Dec;140(3):401-9.
Effects of lifetime exposure to chronic irradiation on reproductive success were assessed for laboratory populations of Neanthes arenaceodentata. Exposure was initiated upon the spawning of the parental (P1) female and was terminated upon spawning of the first filial (F1) generation female; broods from the F1 pairs were sacrificed before hatching occurred. Groups of worms in the experiments received either no radiation (controls) or 0.19, 2.1 or 17 mGy h-1. The total dose received was either background or approximately 0.55, 6.5 or 54 Gy, respectively. The mean number of embryos in the broods from the F1 females exposed to 17 mGy h-1 was statistically significantly different from the mean number of embryos from control females; however, the mean number of embryos in the broods from the F1 females exposed to 0.19 and 2.1 mGy h-1 was not significantly different from the mean number from control females. For all the radiation-exposed groups, there was a statistically significant reduction in the number and percentage of live embryos in the broods from the F1 pairs as well as a statistically significant increase in the numbers and percentages of abnormal embryos. Results on embryo abnormalities and mortalities indicate that dominant- and recessive-lethal mutations were most likely induced in the germ cells and that these mutations had an adverse effect on reproductive success by affecting the survival of early-life stages. Except for pairs exposed to 17 mGy h-1, there was no evidence of gamete killing or reduced fertilization success, because the number of developing embryos in the broods did not decrease with increased dose. Data for the estimated hatch number and actual hatch number indicated that doses as low as 0.19 mGy h-1 can reduce significantly the number of larvae that hatch when lifetime doses are given.
针对沙蚕（Neanthes arenaceodentata）实验室种群，评估了终生暴露于慢性辐射对繁殖成功率的影响。辐射暴露在亲代（P1）雌性产卵时开始，并在第一代子代（F1）雌性产卵时终止；F1代配对产生的卵在孵化前被处死。实验中的蠕虫群体分别接受无辐射（对照组）或0.19、2.1或17 mGy h-1的辐射。所接受的总剂量分别为背景剂量或约0.55、6.5或54 Gy。暴露于17 mGy h-1的F1雌性所产幼体中的胚胎平均数量与对照雌性所产幼体中的胚胎平均数量在统计学上有显著差异；然而，暴露于0.19和2.1 mGy h-1的F1雌性所产幼体中的胚胎平均数量与对照雌性所产幼体中的胚胎平均数量没有显著差异。对于所有辐射暴露组，F1代配对所产幼体中活胚胎的数量和百分比在统计学上有显著减少，异常胚胎的数量和百分比在统计学上有显著增加。胚胎异常和死亡率的结果表明，显性和隐性致死突变很可能在生殖细胞中被诱导，并且这些突变通过影响生命早期阶段的存活对繁殖成功率产生了不利影响。除了暴露于17 mGy h-1的配对外，没有证据表明存在配子杀伤或受精成功率降低，因为幼体中发育胚胎的数量并没有随着剂量增加而减少。估计孵化数量和实际孵化数量的数据表明，当给予终生剂量时，低至0.19 mGy h-1的剂量可显著减少孵化出的幼虫数量。
